var Lists=document.getElementsByTagName("li");
var Areas=document.querySelectorAll('.Dv');
for(var i=0;i<Lists.length;i++){
    Areas[i].setAttribute('index',i);
    Lists[i].onclick = function(){
        for(var j=0;j<Lists.length;j++){
            if(Lists[j]!==this){
                Lists[j].className= '';
            }else{
                this.className='now';
            }
        }
        var index=this.getAttribute('index');
        console.log(index);
        for(var k=0;k<Areas.length;k++){
            if(Areas[k]!==Areas[index]){
                Areas[k].style.display="none";
            }else{
                Areas[index].style.display="block";
            }
        }

    }
}